To whom it may concern:
This thread is for the discussion of Less Wrong topics that have not appeared in recent posts. If a discussion gets unwieldy, celebrate by turning it into a top-level post.
(After the critical success of part II, and the strong box office sales of part III in spite of mixed reviews, will part IV finally see the June Open Thread jump the shark?)
Yes, I would think it would take around 5-10 cigarettes a day (or more) for at least a week to develop an addiction. While cigarettes (and heroin, and caffeine) are very physically addictive, it still takes sustained, moderately high use to develop a physical addiction. Most cigarette smokers describe their addictions in terms of "x packs per day".
Okay, then I guess my case isn't informative ... I'd use the pack/year metric instead instead of the pack/day.